Brake control system for railway trains



Sept 19, 1933- l.. o. GRONDAHL 1,927,437

BRAKE CONTROL SYSTEM FORRAILW'Y TRAINS Filed NOV. 25, 1932 1.4 [10 1 .L l L 15 25 l? f f /Lgg "1?? 21 j u( N f A 7 20 D111 uen by Cil/Axlej l l I l AY l0 ToBr'a/ge /24 Eqaznzan m1/EM HIS A TTORNE Y Patented Sept. 19, 1933 UNITED STATES PATENT OFFICE BRAKE CONTROL SYSTEM FOR RAILWAY TRAINS Application November 2.5,` 1932 Serial No. 644,173

4 claims. (c1. 30s-2o) c My invention relates to brake control systems for railway trains.

I will describe three forms of apparatus embodying my invention, and will then point out the `5 novel features thereof in claims.

In the operation of the brakes of a railway train, it is dilcult to obtain operation of the brakes at the rear end of the train simultaneously with the control set up at the front end of the train. The reason for this Vis the slowness in the propagation of the braking impulse through the-air pressure of the brake pipe. A feature of my invention is the provision of apparatus for expediting a braking impulse through a railway train by propagating the impulse electrically and automatically from one end of a car to the other and then propagating the .impulse pneumatically through the usual hose couplingto the next succeeding car. By such an arrangement, a braking impulse will be transmitted to the rear of a railway train in a relatively short interval of time. Consequenly, a much less time will be required to transmit the braking impulse to the rear end of a. train by the. apparatus of myinvention than is required to transmit the impulse through the brake pipe alone. A further feature of my invention is the provision. of a local source of electrical energy on each car, so that each car operates as a unit andwill `be effective when used-in a train having cars not so equipped. Furthermore, each carwhen operated as a unit will permit the propagating of a braking impulse electrically without the use of train wires, that is, without wires running the full length of a train byv being connected from one car to the next through the medium of a circuit coupler. A still further feature ofmy invention is the provision of apparatus whereby a reduction of brake pipe pressure is assured at all points on a train in 4 response to a braking impulse initiated at the forwardend of the train, notwithstanding variations in the brake pipe pressure along, the brake pipe due to Ydistributed leaks in the brake pipe. Other features of my invention will appear as the specication progresses.

In the accompanying drawing, Fig. lis a dia'- 4grammatic view of one form of apparatus embodying my invention as applied to a singlecar. It will be understood that in practicing my invention each car of a train will preferably be equipped with the apparatus of my invention; However, as will appear later, cars equipped with my'invention, if associated in a train with cars Y not so equipped, will operate to hasten the propagation of Aa braking impulse throughout the train in proportion to the number of cars in the Y train which are so equipped. Fig. 2 is a diagrammatic view of a second form of apparatus also embodying my invention and wherewith only 4the electromagnetic device for the end of a car re- 5K0 mote from the end at which the braking impulse rst appears is energized.V Fig. 3 is a diagrammatic view of the apparatus whereby various degrees of brake application will be quickly propagated from oneend of a car to the other, and which apparatus also embodies my invention.`

In each of the several views like reference characters designate similar parts.

Referring to Fig. l, the reference character 10 70 represents the usual brake pipe extending the full lengthof a railway lcar with a hose coupling 11 at each of the opposite ends of the car. Connected to the brake pipe 10 through the medium of a branch pipe 14 is the usual pneumatic device 75. comprising a triple valve 12 and an auxiliary reservoir 13 for producingthe different operations of the car brakes inthe usual manner. Connected to the brake pipe 10 at opposite ends of the car, and as near to the hose coupling as possible are two branch pipes v15 and 16. v,The branch pipes 15 and 16 are connected to the cylinders, 17 and 18, respectively, which are provided with'diaphragms 19 and 20, respectively. .These diaphragms are each provided with a vent 21 so that 85 the cylinders 17 and 18 in the equilibrium condition will contain on both sides ofV the respective diaphragm, pressure which normally corresponds to the brake pipepressure. Mounted 4on the diaphragm 19 is a contact 22 which is electrically 90 connected to the diaphragm and hence is groundedtok the brake pipe 10. The Contact 22 is adapted to engage, at times, a stationary contact 23 which is insulated from the brake pipe. .In like manner the diaphragm 20 has mountedonit a 95 contact 41 which is adapted to engage, at times,

a stationary contact 42.r The branch pipes 15 and 16 are further connected by the pipes 24 and 25, respectively, to a chamber 26 of electroresponsive devices EV and EVl, respectively. The chamber 26 of each of these electroresponsive devices is connected to an associated cylinder 27 -through a passage 28, the passage being normally closed by a valve 29 biased to the closed position `byfa spring 30. In each device EV and EVl, the spring 30 upon closing the valvef29 also raises a valve 31 to the open position andthe associated cylinder 27 is vented to the atmosphere through a port 32. The energizing of the winding of a magnet33 associated with the device4 EV will close the valve 31 110v that the cylinder 27 associated with device EVl is` connected to the brake pipe 10. It follows that energizing either of the magnets 33 or 34-will cause a reduction of the brake pipe pressure, a certain amount of air pressure being exhausted into the associated cylinder 27 which is normally at atmospheric pressure.

Each car is preferably equipped with a source of current, such for example, as the axle driven direct current generator 35. Generator 35 may be mounted either directly on the axle of the car, belt driven or gear driven from an axle, all three methods being well known. While generator 35 is shown as a direct current generator, it Will be understood that it may be an alternating current generator or a battery properly housed, the reference character V35 designating apparatus by which electrical energy is obtained locally on the car and which energy is of a form proper for the energizing of the magnets 33 and 34. The vcurrent source 35 preferably has one terminal grounded to the brake pipe 10 as indicated at point 39 of Fig. 1.

Assuming that the locomotive of the train is to the left of the car of Fig. 1 and a reduction of the brake pipe pressure is initiated on the locomotive for establishing an application of the train brakes, the reduction of the brake pipe pressure upon reaching the branch pipe 15 will cause a reduction of the pressure on the top side of the diaphragm 19. Diaphragm 19 will be forced upward dueto the higher pressure on the lower side and thus will bring the contact22 into engagement with the stationary contact 23. Current will now flowY from the local source 35 along wire 36, winding of magnet 34, wire 37, winding of magnet 33, wire 38, contact 22-23, the brake pipe V10 for the car and hence by wire 40 to the opposite terminal of the current source 35. The energizing of the magnet 34 of the device EV1 at the far end of the car will close the exhaust to its cylinder 27 and connect the cylinder to the brake pipe 10l and air under pressure will flow from the brake pipe 10 into the cylinder 27 as suddenly as permissible, producing a reduction in the brake pipe pressure at rthe far end of the car. This reduction will be transmitted through the hose coupling 11 to the branch pipe 15a (see Fig. 2) for the equipment of the car next in the rear where the'operation just described Will be repeated. The energizing of the magnet 33 of the device EV closes its valve 31 and opens its valve 29 and a certain amount of air under pressure will flow from the brake pipe into the cylinder 27 for the device EV. YThe reduction of the brake pipe pressure at the far end of the car Will cause the diaphragm 20 to be forced upward and the associated contacts 4l and 42 brought into engagement. 'Ihis engagement of contacts 41 and 42will result only in the closing of another connection of the above traced circuit to the brake pipe, and will, at this time, serve no useful function. In the meantime, the air pressure is being lequalized on the two sides of the diaphragm 19 and also on the twosides of the diaphragm 20 due to the vent 21 in each diaphragm, with the result that very-soon these diaphragms will assume their normalposition, that is, the position indicated in Fig. l, and the circuit to the magnets 33 and 34 will be opened leaving them without energy. Deenergizing the magnets 33 and 34 permits the valve 29 of each device to be closed, and the valve 31 to be opened by the biasing spring 30 and the air pressure collected in the cylinders 27 is exhausted to atmosphere through the port 32.

From the foregoing descripion of the apparatus of Fig. l, it is clear that a braking impulse appearing at the' left-hand end of Fig. 1 will be propagated to the right-hand end electrically Which will require la much shorter interval of time than the present method of transmitting the impulse through the air pressure of the brake pipe. The reduction of the brake pipe pressure effected at the right-hand end of Fig. l will be transmitted through the hose coupling to the branch pipe 15a for the car next to the right, and, consequently, the braking impulse initiated on the locomotive, which I have here assumed to be at the left of Fig. 1, will be propagated'the entire length of the train at a rate that will materially .reduce the time required for the braking impulse to reach the rear end of the train from the time required by the present method in general use.

Furthermore, it is well known that with a leaky brake pipe it is sometimes diiiicult to obtain a brake application at all on the part of the train furthest removed from the locomotive. The apparatus of Fig. 1 removes a denite volume of air from the brake pipe at each car, with the result that even at the rear of the train, where the pressure may be relatively low due to `the distributed leaks along the train, a pressure reduction great enough to initiate a brake application will be obtained. It will be understood, of course, that the parts of the. apparatus are so proportioned and adjusted that ,the volume of air taken out of the brake pipe and the rate of removing the air will be such as to avoid a reverse transmission of the impulse, and will not constitute a serious handicap in recharging the brake pipe.

In the event the braking impulse is travelling from the right to the left in Fig. 1, the reduction of the brake pipe pressure appearing at the branch pipe 16 will reduce the pressure above the diaphragm 20 of cylinder 18 and the diaphragm 20 will be forced upward and cause contact 41 to engage the stationary contact 42. Closing the contact 41-42 permits current to fiow from the generator 35 along wire 36, winding'of magnet 34, wire 37, winding of magnet A33, Wires 38 and 43, Contact 41-42. and thence through the brake pipe and wire 40 to the opposite terminal of generator 35. The energizing ofv the `magnet 33 will cause the device EV at the left-hand end of the car to function to reduce the brake pipe pressure and which reduction will then be passed on through the hose coupling to the car next to the left. The energizing of magnet 34 will, of course, vent a certain amount of air from the brake pipe 10 to the cylinder v27 of Ithe device EVl. In a very short interval of time the two diaphragms 19 and 2D will .be restored to `their normall position and the circuit to magnetsV 33 and 34 will be opened with the result that-the devices EV and'EVl quickly assume their normal condition. Consequently, a braking impulse will be transmittedV electrically from the righthand end to the left-hand end of the car in the same manner as described hereinbefore for the braking impulse travellingI from the left to the right.

To obtain various degrees of brake application the apparatus of Fig. l can be operated repeatedly. vFor example, if-one vreduction measured by the volume of air taken out of the brake pipe corresponds to an 8 pound reduction in the brakev pipe pressure, and if this reduction is not suicient, a second reduction can be eifected as soon as the diaphragms 19 and 2i) have .been'restored to their normal position. This'second reduction will then cause the devices EV and EVl to 'func-V tion a second time to secure an increase in the brake application.

VIn the form of my invention disclosed in Fig. 2, only the electropneumatic device at the end of the car remote-from the initiating braking impulse is active. Assume a reduction of brake' pipe 'pressure appears at the left-hand end of Fig. 2, the diaphragm 19k of cylinder `17 will be forced upward to close the contact-ZZ-ZB and current will ow from the generator 35 through wire 36, winding of magnet 34; wire 37,4contact 51 operated by the magnetB-i and closed only when that magnet is deenerg'ized, wire 52, contact 22-23,'brake pipe 10 and wire 40 to the opposite terminal of generator 35. The energizing of magnet 34 not only operates the valves 29 and 3l. of'device EVl, but also opens acontact 53 included in the circuit for the magnet 33 as will shortly appear. vBy operating valves 29 and 3l. the device EVl is caused to function to create a brake pipe pressure reduction atv the rear end of the car the same as described for Fig. 1. While this reduction in the brake pipe pressure at the rear end of the lcar will cause the diaphragm 2o to be forced upwardrto close the contact 4l--42, themagnet "3 can notrbe energized due to the fact that the contact `53 'operated by magnet 34 and closed only when'that magnet is deenergized,

is now open. Hence, the braking impulse appearing at Vthe left-h`and end of Fig. 2 is transmitted to the right-hand end of the car electrically, but the device EV at theleft-hand end of the car is maintained inactive.'v The'brake pipe reduction established at the right-hand end of Fig. 2 will be passed through the coupiing 1lv to the branch pipe 152L for the car next to the'rear and thus it follows that the braking impuse will be propagated the full length of the train in the same manner as obtained in Fig. 1.

In the. event the braking impulse appears at the right-hand end of Fig. 2 the diaphragm of cylinder 18 will be forced upward to close the contact 41-42 and current will now fromlthe generator 35 v'along wire 54, winding of magnet 33, wire 43, contactgf operated by magnet 34, contact Ll1---42, brake pipe and Awire 4G to the opposite terminaliof generator 35. This time magnet 33 isenergized first, operating the device EV and also opening the contact 5l in the circuit for magnet 34. The device EV will now function to produce a reduction of the brake pipe pressure at the left-hand end of the car which will be passed through the hose coupling 11 to the car next to the left. Although the diaphragm 19 will be forced upward to close the contact 22-23, the circuit to the magnet 34 is held open at the contactl. It follows that a braking impulse is transmitted electrically in either direction by the apparatus of Fig. 2, the device EV or EVl `remote from the initiating impulse being rendered active only.

The apparatus disclosed in Fig. 3 permits varito this relatively heavy braking impulse will cause ous degrees of reduction in the brake pipe pressure to be established in accordance with'various degrees of the initiating impulse. That is, if only a light brake application is initiated on the locomotive, a corresponding volume of air is removed from the brake pipe, but if a heavier brake application is initiated on the locomotive an additional volume of air is removed from the brake pipe.

Assuming a relatively light brake application appears at the branch pipe 15 at the left-hand end of Fig. 3, the diaphragm 19 in cylinder 17 will be forced upward just far enough to close the contact 122-23. Current will now fiow from the local current source, here indicated as a battery 35A, to the magnet 34 overa circuit similar to that traced for Fig. 2, and which circuit includes the Contact 51 operated byfmagnet 33 and the contact 22-23- Energizing the magnet 34 opens the cylinder 27 of device E171 to the brake pipe and a certain reduction of air pres-v sure is eected at the right-hand end of the car, this reduction corresponding tothe initiating braking impulse. The energizing of magnet 34 also opens the contact 53 in a circuit for magnet 33 and the device EV is retained inactive in the same manner as described for Fig. 2. The pressure on the two sides of the diaphragm 19 will soon be equalized and the device EVl will then be restored to its normal position. It follows that the light braking impulse appearing at the lefthand end of Fig. 3 causes the removal of a certain volume of air from the brake pipe at the right-hand end of the car, which effects a corresponding reduction of brake pipe pressure at that point. Let us now assume that in place of a light braking impulse a relatively heavy braking impulse appears at the branch pipe l5. The reduction of brake pipe pressure corresponding the diaphragm 19 to be forced upward far enough to not only close thecontact 22-23 but to also close a second contact 22-44. The. closing of the contact 22--23 will result in the functioning of the device EVl in the manner just ydescribed 12d and a certain volume of air is removed from the brake pipe at the rear end of the car by that device. The closing of the contact 22-44 results in current flowing from the source 35A through winding of magnet 45 of an electropneuinatic device EV2, wire 46, contact 56 operated by magnet 47 of an electropneumatic device EVS, wire 48, Contact 22-44, brake pipe 10 and thence by wire 49 back to the battery 35A. The electropneumatic devices EVZ and EV3 are preferably 130 similar in all respects to the devices EV and EVl. Hence, the energizing of magnet 45 of the device EV2 opens the associated cylinder 5G to the brake pipe 19 and angadditional volume of air is removed from the brake pipe, this additional vol- '13a urne being sufficient to cause a relatively heavy reduction in the brake pipe pressure at the rear end of the car. The energizing of magnet 45 opens the contact 58 which is included in the circuit for the magnet 47 as will shortly appear. 143 As soon as the pressure on both sides of the diaphragm 19 is equalized the circuits to both magnets 34and 45 are opened and both devices EVl Y and EVB are restored to their normal condition.

1t follows that in response to a relatively heavy 145 impulse appearing at the branch pipe 15 a suft`1. cient volume of air is removed from the brake pipe at the rear end of the car to effect a relatively heavy reduction in the brake pipe pressure.

In the event a braking impulse appears at the right-hand end of Fig. 3, and this impulse corresponds to a light brake application, the diaphragm 20 in cylinder 18 is forced upward only far enough to close the contact 41-42 and current will flow from the battery 35A over Wire 54, winding of magnet 33, wire 43, contact 53 of magnet 34, contact 41-42, brake pipe and connection 49 back to the battery 35A. The

energizing of magnet 33 results in the associated cylinder of device EV being opened to the brake pipe 10 and a volume of air removed which is suicient to effect a light reduction in the brake pipe pressure at the left-hand end of the car. The energizing of magnet 33 also opens the contact 5l in a circuit for magnet 34 to maintain device EVl inactive. If the impulse appearing at the branch pipe i6 of Fig. 3 corresponds to a relatively heavy brake application, the diaphragm 20 will be forced upward far enough to not only close the contact 41-42 but to also close a second contact 4l-55. Closing the contact 41-42 causes the device EV to be active in the manner just described, andthe closing of the contact 41-55 permits current to flow from the battery 35A over wire 54, magnet 47 of device EVS, Wire 57, contact 58 of magnet 45, wire 59, contact 141-55, brake pipe and thence by wire 49 back to the battery 35A. Energizing magnet 47 causes the device EVS to open its associated cylinder to the brake pipe and an additional volume of air is removed from the brake pipe at the left-hand end of the car. It is clear, therefore, that a light brake impulse appearing at the right-hand end of Fig. 3 results in a light reduction in the brake pipe pressure at the left-hand end, and a relatively heavy braking impulse appearing at the righthand end of the car results in a relatively heavy reduction in the brake pipe pressure at the lefthand end of the car. While I am here assuming that two degrees of brake pipe reduction are sufcient, it is clear that a greater number can be obtained, should it seem desirable to do so, by adding devices similar to devices EV2 and EVB to the apparatus of Fig. 3.

Apparatus such as here disclosed will propagate a braking impulse electrically without the necessity of train wires extending from one car to the next, and will very materially reduce the time required to propagate a braking impulse to the rear end of a train from that required when the braking impulse is propagated through the brake pipe alone. Furthermore, with the apparatus here disclosed, a brake application is assured at the rear end of a train even though there may exist variations in the brake pipe pressure due to the distributed leaks along the brake pipe.

Although I have herein shown and described only three forms of aparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a fluid pressure brake system for railway trains, the combination with the brake pipe, of an electroresponsive device for each end of a car, means governed by each electroresponsive device for producing a reduction of brake pipe pressure, local means on such car for producing electrical energy, controlling means at each end of the car responsive to a reduction of brake pipe pressure for supplying energy from said local means to the electroresponsive device at the opposite end of the car for transmitting a braking impulse electrically from one end of the car to the other, and means governed by each electroresponsive means effective when said electroresponsive means is active in making a reduction in the brake pipe pressure to prevent the supply of energy to the other electroresponsive device.

2. In a fiuid pressure brake system for railway trains, the combination with the brake pipe, of an electroresponsive device at each end of a car adapted to effect a reduction of the brake pipe pressure but normally inactive, controlling means at each end of such car responsive to a reduction of brake pipe pressure to render the electroresponsive means at the end of the car opposite the controlling means active to reduce the brake pipe pressure, and means controlled by each electroresponsive device in its active condition to maintain the other electroresponsive device inactive.

3. In a fluid pressure brake system for railway trains, the combination with the brake pipe, of a plurality of electroresponsive devices fora car, means operated by each electroresponsive device for producing a given reduction in the brake pipe pressure at the rear end of such car, a local source of electrical energy on the car, controlling means selectively responsive to diiferent degrees of reduction in the brake pipe pressure at the forward end of the car for selectively supplying energy from said local source to the electroresponsive devices for establishing a degree of brake `pipe reduction at the rear of the car in accordance with the degree of reduction appearing at the forward end of the car.

4. In a fluid pressure brake system for railway trains, the combination with the brake pipe, of a plurality of brake pipe pressure governing devices connected to the brake pipe at the rear end of a car and each adapted when operated to produce a given reduction in the brake pipe pressure, a controlling means connected to the brake pipe at the forward end of such car and selectively responsive to different degrees of reduction in the brake pipe pressure, and means governed by said controlling means to selectively operate said pressure governing devices to establish at the rear end of the car a reduction in the brake pipe pressure corresponding to that appearing at the forward end of the car.

' LARS O. GRONDAHL. 

